Terminal device, base station device, communication method, and integrated circuit

ABSTRACT

A terminal device and a base station device can efficiently communicate with each other by using a downlink channel. The terminal device monitors, in an EPDCCH-PRB-set p in a subframe k, a first set ESk(L) of first EPDCCH candidates and a second set ESk(L) of second EPDCCH candidates. A first number Mp,c(L) of the first EPDCCH candidates is determined according to a first αp,c and Mp(L), and a second number Mp,c(L) of the second EPDCCH candidates is determined according to a second αp,c and Mp(L). First ECCE(s) corresponding to an mth first EPDCCH candidate included in the first set ESk(L) and a-second ECCE(s) corresponding to an mth second EPDCCH candidate included in the second set are determined according to a first value. The first value is given by a following expression, where NECCE,p,k is a total number of ECCEs included in the EPDCCH-PRB-set p in the subframe k.

TECHNICAL FIELD

The present invention relates to a terminal device, a base stationdevice, a communication method, and an integrated circuit.

This application claims priority based on JP 2015-218218 filed on Nov.6, 2015, the contents of which are incorporated herein by reference.

BACKGROUND ART

In the 3rd Generation Partnership Project (3GPP), a radio access methodand a radio network for cellular mobile communications (hereinafter,referred to as “Long Term Evolution (LTE)”, or “Evolved UniversalTerrestrial Radio Access (EUTRA)”) have been studied. In LTE, a basestation device is also referred to as an evolved NodeB (eNodeB), and aterminal device is also referred to as a User Equipment (UE). LTE is acellular communication system in which multiple areas each covered bythe base station device are deployed to form a cellular structure. Asingle base station device may manage multiple cells.

In 3GPP, career aggregation has been specified which allows a terminaldevice to perform simultaneous transmission and/or reception in multipleserving cells (component careers).

NPL 1 proposes configuring, for each serving cell and aggregation level,the number of PDCCH candidates included in a User Equipment-specificSearch Space (USS) monitored by a terminal device. Furthermore, NPL 1proposes introducing, for each serving cell, deactivation of monitoringof a DCI format 0/1A.

CITATION LIST Non Patent Literature

NPL 1: “WF on number of blind decodes”, R1-156130, Nokia Networks,Lenovo.

NPL 2: “3GPP TS 36.211 V12.7.0 (2015-09)”, 25 Sep. 2015.

NPL 3: “3GPP TS 36.212 V12.6.0 (2015-09)”, 25 Sep. 2015.

NPL 4: “3GPP TS 36.213 V12.7.0 (2015-03)”, 25 Sep. 2015.

SUMMARY OF INVENTION Problems to be Solved by the Invention

The present invention provides a terminal device capable of efficientlycommunicating with a base station device by using a downlink channel, abase station device communicating with the terminal device, acommunication method used for the terminal device, a communicationmethod used for the base station device, an integrated circuit mountedon the terminal device, and an integrated circuit mounted on the basestation device. For example, a USS monitored by the terminal device isefficiently designed/defined. The communication method used for theterminal device may include an efficient method of monitoring the USS bythe terminal device. The communication method used for the base stationdevice may include an efficient transmission method in a downlinkchannel to the terminal device.

Means for Solving the Problems

(1) According to some aspects of the present invention, the followingmeasures are provided. That is, a first aspect of the present inventionis a terminal device, including an antenna unit configured to receive anEnhanced Physical Downlink Control Channel (EPDCCH); and a radiotransmission and/or reception unit configured to monitor, in anEPDCCH-PRB-set p in a subframe k, a first set ES_(k) ^((L)) of firstEPDCCH candidates and a second set ES_(k) ^((L)) of second EPDCCHcandidates. The first set ES_(k) ^((L)) corresponds to a first CarrierIndicator Field (CIF) value and a first aggregation level L, and thesecond set ES_(k) ^((L)) corresponds to a second CIF value and the firstaggregation level L. A first number M_(p,c) ^((L)) of the first EPDCCHcandidates is determined according to at least α_(p,c) indicated byfirst information and M_(p) ^((L)), and a second number M_(p,c) ^((L))of the second EPDCCH candidates is determined according to at leastα_(p,c) indicated by second information and the M_(p) ^((L)). A firstEnhanced Control Channel Element (ECCE) corresponding to the m^(th)first EPDCCH candidate included in the first set ES_(k) ^((L)) and asecond ECCE corresponding to the m^(th) second EPDCCH candidate includedin the second set are determined according to at least a first value.The first value is given by an expression below, where N_(ECCE,p,k) is atotal number of ECCEs included in the EPDCCH-PRB-set p in the subframek, and floor is a function returning a value obtained by rounding downan input value after the decimal point.

$\begin{matrix}{{{{floor}\left( \frac{m \cdot N_{{ECCE},p,k}}{L \cdot M_{p}^{(L)}} \right)}\mspace{14mu} {where}}{{m = 0},1,\ldots \mspace{14mu},{M_{p,c}^{(L)} - 1}}} & \left\lbrack {{Expression}\mspace{14mu} 1} \right\rbrack\end{matrix}$

(2) A second aspect of the present invention is a base station device,including a radio transmission and/or reception unit configured to codeDownlink Control Information transmitted by using an Enhanced PhysicalDownlink Control Channel (EPDCCH); and an antenna unit configured totransmit the EPDCCH in each of a first set ES_(k) ^((L)) of first EPDCCHcandidates and a second set ES_(k) ^((L)) of second EPDCCH candidates inan EPDCCH-PRB-set p in a subframe k. The first set ES_(k) ^((L))corresponds to a first Carrier Indicator Field (CIF) value and a firstaggregation level L, and the second set ES_(k) ^((L)) corresponds to asecond CIF value and the first aggregation level L. A first numberM_(p,c) ^((L)) of the first EPDCCH candidates is determined according toat least α_(p,c) indicated by first information and M_(p) ^((L)), and asecond number M_(p,c) ^((L)) of the second EPDCCH candidates isdetermined according to at least α_(p,c) indicated by second informationand the M_(p) ^((L)). A first Enhanced Control Channel Element (ECCE)corresponding to the m^(th) first EPDCCH candidate included in the firstset ES_(k) ^((L)) and a second ECCE corresponding to the m^(th) secondEPDCCH candidate included in the second set are determined according toat least a first value. The first value is given by an expression below,where N_(ECCE,p,k) is a total number of ECCEs included in theEPDCCH-PRB-set p in the subframe k, and floor is a function returning avalue obtained by rounding down an input value after the decimal point.

$\begin{matrix}{{{{floor}\left( \frac{m \cdot N_{{ECCE},p,k}}{L \cdot M_{p}^{(L)}} \right)}\mspace{14mu} {where}}{{m = 0},1,\ldots \mspace{14mu},{M_{p,c}^{(L)} - 1}}} & \left\lbrack {{Expression}\mspace{14mu} 2} \right\rbrack\end{matrix}$

(3) A third aspect of the present invention is a communication methodused for a terminal device, the method including the steps of: receivingan Enhanced Physical Downlink Control Channel (EPDCCH); and monitoring,in an EPDCCH-PRB-set p in a subframe k, a first set ES_(k) ^((L)) offirst EPDCCH candidates and a second set ES_(k) ^((L)) of second EPDCCHcandidates. The first set ES_(k) ^((L)) corresponds to a first CarrierIndicator Field (CIF) value and a first aggregation level L, and thesecond set ES_(k) ^((L)) corresponds to a second CIF value and the firstaggregation level L. A first number M_(p,c) ^((L)) of the first EPDCCHcandidates is determined according to at least α_(p,c) indicated byfirst information and M_(p) ^((L)), and a second number M_(p,c) ^((L))of the second EPDCCH candidates is determined according to at leastα_(p,c) indicated by second information and the M_(p) ^((L)). A firstEnhanced Control Channel Element (ECCE) corresponding to the m^(th)first EPDCCH candidate included in the first set ES_(k) ^((L)) and asecond ECCE corresponding to the m^(th) second EPDCCH candidate includedin the second set are determined according to at least a first value.The first value is given by an expression below, where N_(ECCE,p,k) is atotal number of ECCEs included in the EPDCCH-PRB-set p in the subframek, and floor is a function returning a value obtained by rounding downan input value after the decimal point.

$\begin{matrix}{{{{floor}\left( \frac{m \cdot N_{{ECCE},p,k}}{L \cdot M_{p}^{(L)}} \right)}\mspace{14mu} {where}}{{m = 0},1,\ldots \mspace{14mu},{M_{p,c}^{(L)} - 1}}} & \left\lbrack {{Expression}\mspace{14mu} 3} \right\rbrack\end{matrix}$

(4) A fourth aspect of the present invention is a communication methodused for a base station device, the method including the steps of:coding Downlink Control Information transmitted by using an EnhancedPhysical Downlink Control Channel (EPDCCH); and transmitting the EPDCCHin each of a first set ES_(k) ^((L)) of first EPDCCH candidates and asecond set ES_(k) ^((L)) of second EPDCCH candidates in anEPDCCH-PRB-set p in a subframe k. The first set ES_(k) ^((L))corresponds to a first Carrier Indicator Field (CIF) value and a firstaggregation level L, and the second set ES_(k) ^((L)) corresponds to asecond CIF value and the first aggregation level L. A first numberM_(p,c) ^((L)) of the first EPDCCH candidates is determined according toat least α_(p,c) indicated by first information and M_(p) ^((L)), and asecond number M_(p,c) ^((L)) of the second EPDCCH candidates isdetermined according to at least α_(p,c) indicated by second informationand the M_(p) ^((L)). A first Enhanced Control Channel Element (ECCE)corresponding to the m^(th) first EPDCCH candidate included in the firstset ES_(k) ^((L)) and a second ECCE corresponding to the m^(th) secondEPDCCH candidate included in the second set are determined according toat least a first value. The first value is given by an expression below,where N_(ECCE,p,k) is a total number of ECCEs included in theEPDCCH-PRB-set p in the subframe k, and floor is a function returning avalue obtained by rounding down an input value after the decimal point.

$\begin{matrix}{{{{floor}\left( \frac{m \cdot N_{{ECCE},p,k}}{L \cdot M_{p}^{(L)}} \right)}\mspace{14mu} {where}}{{m = 0},1,\ldots \mspace{14mu},{M_{p,c}^{(L)} - 1}}} & \left\lbrack {{Expression}\mspace{14mu} 4} \right\rbrack\end{matrix}$

Effects of the Invention

According to the present invention, a terminal device and a base stationdevice can efficiently communicate with each other by using a downlinkchannel

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a conceptual diagram of a radio communication system accordingto the present embodiment.

FIG. 2 is a diagram illustrating a schematic configuration of a radioframe according to the present embodiment.

FIG. 3 is a diagram illustrating a schematic configuration of a downlinkslot according to the present embodiment.

FIG. 4 is a diagram illustrating an example of downlink signal mappingaccording to the present embodiment.

FIG. 5 is a diagram illustrating an example of a transmission process ofDownlink Control Information according to the present embodiment.

FIG. 6 is a diagram illustrating an example of PDCCH USSs in onesubframe k of one serving cell according to the present embodiment.

FIG. 7 is a diagram illustrating an example of PDCCH USSs in onesubframe k of one serving cell according to the present embodiment.

FIG. 8 is a diagram illustrating an example of PDCCH USSs in onesubframe k of one serving cell according to the present embodiment.

FIG. 9 is a diagram illustrating an example of EPDCCH USSs in one EPDCCHset p in one subframe k of one serving cell according to the presentembodiment.

FIG. 10 is a diagram illustrating an example of EPDCCH USSs in oneEPDCCH set p in one subframe k of one serving cell according to thepresent embodiment.

FIG. 11 is a diagram illustrating an example of EPDCCH USSs in oneEPDCCH set p in one subframe k of one serving cell according to thepresent embodiment.

FIG. 12 is a diagram illustrating an example of EPDCCH USSs in oneEPDCCH set p in one subframe k of one serving cell according to thepresent embodiment.

FIG. 13 is a diagram illustrating a correspondence between a DCI formatand a USS in a case that monitoring of a DCI format 0/1A for a servingcell c1 corresponding to a CIF value 1 is not deactivated, according tothe present embodiment.

FIG. 14 is a diagram illustrating a correspondence between the DCIformat and the USS in a case that the monitoring of the DCI format 0/1Afor the serving cell c1 corresponding to the CIF value 1 is deactivated,according to the present embodiment.

FIG. 15 is a diagram illustrating a correspondence between the DCIformat and the USS in the case that the monitoring of the DCI format0/1A for the serving cell c1 corresponding to the CIF value 1 isdeactivated, according to the present embodiment.

FIG. 16 is a schematic block diagram illustrating a constitution of aterminal device 1 according to the present embodiment.

FIG. 17 is a schematic block diagram illustrating a constitution of abase station device 3 according to the present embodiment.

Mode for Carrying Out the Invention

Embodiments of the present invention will be described below.

FIG. 1 is a conceptual diagram of a radio communication system accordingto the present embodiment. In FIG. 1, the radio communication systemincludes terminal devices 1A to 1C and a base station device 3. Each ofthe terminal devices 1A to 1C is referred to as a terminal device 1below.

Now, carrier aggregation will be described.

In the present embodiment, multiple serving cells are configured for theterminal device 1. A technology in which the terminal device 1communicates via the multiple serving cells is referred to as cellaggregation or carrier aggregation. The present invention may be appliedto each of the multiple serving cells configured for the terminal device1. Furthermore, the present invention may be applied to some of theconfigured multiple serving cells. Furthermore, the present inventionmay be applied to each of groups of the configured multiple servingcells. Furthermore, the present invention may be applied to some of thegroups of the configured multiple serving cells. In carrier aggregation,the configured multiple serving cells are also referred to as aggregatedserving cells.

Time Division Duplex (TDD) and/or Frequency Division Duplex (FDD) isapplied to a radio communication system in the present embodiment. In acase of cell aggregation, serving cells to which TDD is applied andserving cells to which FDD is applied may be aggregated.

The configured multiple serving cells include one primary cell and oneor multiple secondary cells. The primary cell is a serving cell in whichan initial connection establishment procedure has been performed, aserving cell in which a connection re-establishment procedure has beenstarted, or a cell indicated as a primary cell during a handoverprocedure. At the point in time when a Radio Resource Control (RRC)connection is established, or later, a secondary cell may be configured.

A carrier corresponding to a serving cell in the downlink is referred toas a downlink component carrier. A carrier corresponding to a servingcell in the uplink is referred to as an uplink component carrier. Thedownlink component carrier and the uplink component carrier arecollectively referred to as a component carrier.

The terminal device 1 can perform simultaneous transmission on multiplephysical channels/of multiple physical signals in the multiple servingcells (component careers) to be aggregated. The terminal device 1 canperform simultaneous reception on multiple physical channels/of multiplephysical signals in the multiple serving cells (component careers) to beaggregated.

FIG. 2 is a diagram illustrating a schematic configuration of a radioframe according to the present embodiment. In FIG. 2, the horizontalaxis is a time axis.

Various field sizes in a time domain are expressed by the number of timeunits Ts=1/(15000×2048) seconds. The length of the radio frame isTf=307200×Ts=10 ms. Each of the radio frames includes ten contiguoussubframes in the time domain. The length of each subframe isTsubframe=30720×Ts=1 ms. Each of the subframes i includes two contiguousslots in the time domain. The two contiguous slots in the time domainare a slot having a slot number ns of 2i in the radio frame and a slothaving a slot number ns of 2i+1 in the radio frame. The length of eachslot is Tslot=153600×ns=0.5 ms. Each of the radio frames includes tencontiguous subframes in the time domain. Each of the radio framesincludes 20 contiguous slots (ns=0, 1, . . . , 19) in the time domain.

A constitution of a slot according to the present embodiment will bedescribed below. FIG. 3 is a diagram illustrating a schematicconfiguration of a downlink slot according to the present embodiment.FIG. 3 illustrates a constitution of a downlink slot in one cell. InFIG. 3, the horizontal axis is a time axis, and the vertical axis is afrequency axis. In FIG. 3, 1 is an orthogonal frequency-divisionmultiplexing (OFDM) symbol number/index, and k is a subcarriernumber/index.

The physical signal or the physical channel transmitted in each of theslots is expressed by a resource grid. In the downlink, the resourcegrid is defined by multiple subcarriers and multiple OFDM symbols. Eachelement within the resource grid is referred to as a resource element.The resource element is expressed by a subcarrier number/index k and anOFDM symbol number/index l.

The resource grid is defined for each antenna port. In the presentembodiment, description is given for one antenna port. The presentembodiment may be applied to each of multiple antenna ports.

The downlink slot includes multiple OFDM symbols l (1=0, 1, . . . , andNDLsymb) in the time domain. NDLsymb indicates the number of OFDMsymbols included in one downlink slot. For a normal Cyclic Prefix (CP),NDLsymb is 7. For an extended Cyclic Prefix (CP), NDLsymb is 6.

The downlink slot includes multiple subcarriers k (k=0, 1, . . . ,NDLRB×NRBsc) in a frequency domain. NDLRB is a downlink bandwidthconfiguration for a serving cell, which is expressed by a multiple ofNRBsc. NRBsc is a (physical) resource block size in the frequencydomain, which is expressed by the number of subcarriers. In the presentembodiment, a subcarrier interval Δf is 15 kHz, and NRBsc is 12subcarriers. That is, in the present embodiment, NRBsc is 180 kHz.

A resource block is used to express mapping of a physical channel toresource elements. For the resource block, a virtual resource block anda physical resource block are defined. The physical channel is firstmapped to the virtual resource block. Thereafter, the virtual resourceblock is mapped to the physical resource block. One physical resourceblock is defined by NDLsymb contiguous OFDM symbols in the time domainand by NRBsc contiguous subcarriers in the frequency domain. Hence, onephysical resource block is constituted by (NDLsymb×NRBsc) resourceelements. One physical resource block corresponds to one slot in thetime domain. The physical resource blocks are numbered/indexed (0, 1, .. . , NDLRB−1) in an order starting from a lower frequency in thefrequency domain.

Physical channels and physical signals in the present embodiment will bedescribed.

In FIG. 1, the following uplink physical channels are used for uplinkradio communication from the terminal device 1 to the base stationdevice 3. The uplink physical channels are used by a physical layer fortransmission of information output from a higher layer.

Physical Uplink Control Channel (PUCCH)

Physical Uplink Shared Channel (PUSCH)

Physical Random Access Channel (PRACH)

The PUCCH is used for transmission of Uplink Control Information (UCI).

The PUSCH is used for transmission of uplink data (UpLink-Shared Channel(UL-SCH)) and/or Uplink Control Information.

The PRACH is used for transmission of a random access preamble (randomaccess message 1).

In FIG. 1, the following uplink physical signal is used in the uplinkradio communication. The uplink physical signal is not used fortransmission of information output from the higher layer, but is used bythe physical layer.

Uplink Reference Signal (UL RS)

In the present embodiment, the following two types of uplink referencesignals are used.

Demodulation Reference Signal (DMRS)

Sounding Reference Signal (SRS)

In FIG. 1, the following downlink physical channels are used fordownlink radio communication from the base station device 3 to theterminal device 1. The downlink physical channels are used by thephysical layer for transmission of information output from the higherlayer.

Physical Broadcast Channel (PBCH)

Physical Control Format Indicator Channel (PCFICH)

Physical Hybrid automatic repeat request Indicator Channel (PHICH)

Physical Downlink Control Channel (PDCCH)

Enhanced Physical Downlink Control Channel (EPDCCH)

Physical Downlink Shared Channel (PDSCH)

Physical Multicast Channel (PMCH)

The PBCH is used for broadcasting a Master Information Block (MIB,Broadcast Channel (BCH)), that is shared by the terminal devices 1.

The PCFICH is used for transmission of information indicating a region(OFDM symbols) to be used for transmission of the PDCCH in a subframe,in which the PCFICH is transmitted.

The PHICH is used for transmission of a HARQ indicator indicating anAcknowledgement (ACK) or a Negative Acknowledgement (NACK) for theuplink data (Uplink Shared Channel (UL-SCH)) received by the basestation device 3.

The PDCCH and the EPDCCH are used for transmission of Downlink ControlInformation (DCI). The Downlink Control Information is also referred toas a DCI format. The Downlink Control Information is mapped to a fieldof the DCI format. The Downlink Control Information includes a downlinkgrant and an uplink grant. The downlink grant is also referred to asdownlink assignment or downlink allocation.

One downlink grant is used for scheduling of one PDSCH within oneserving cell. The downlink grant is used for scheduling of the PDSCHwithin a subframe same as the subframe in which the downlink grant istransmitted.

One uplink grant is used for scheduling of one PUSCH within one servingcell. The uplink grant is used for scheduling of the PUSCH within thefourth or later subframe from the subframe in which the uplink grant istransmitted.

CRC parity bits attached to the downlink grant or the uplink grant arescrambled with a Cell-Radio Network Temporary Identifier (C-RNTI) or aSemi Persistent Scheduling (SPS) Cell-Radio Network Temporary Identifier(C-RNTI). The C-RNTI and the SPS C-RNTI are identifiers for identifyinga terminal device within a cell. The C-RNTI is used to control the PDSCHor the PUSCH in one subframe. The SPS C-RNTI is used to periodicallyallocate a resource for the PDSCH or the PUSCH.

The PDSCH is used for transmission of downlink data (Downlink SharedChannel (DL-SCH)).

The PMCH is used for transmission of multicast data (Multicast Channel(MCH)).

In FIG. 1, the following downlink physical signals are used in thedownlink radio communication. The downlink physical signals are not usedfor transmission of information output from the higher layer, but areused by the physical layer.

Synchronization signal (SS)

Downlink Reference Signal (DL RS)

The Synchronization signal is used in order for the terminal device 1 tobe synchronized to frequency and time domains in the downlink.

The Downlink Reference Signal is used in order for the terminal device 1to perform channel compensation on a downlink physical channel TheDownlink Reference Signal is used in order for the terminal device 1 tocalculate downlink channel state information.

In the present embodiment, the following seven types of DownlinkReference Signals are used.

Cell-specific Reference Signal (CRS)

UE-specific Reference Signal (URS) associated with the PDSCH

Demodulation Reference Signal (DMRS) associated with the EPDCCH

Non-Zero Power Chanel State Information-Reference Signal (NZP CSI-RS)

Zero Power Chanel State Information-Reference Signal (ZP CSI-RS)

Multimedia Broadcast and Multicast Service over Single Frequency NetworkReference Signal (MBSFN RS)

Positioning Reference Signal (PRS)

The downlink physical channels and the downlink physical signals arecollectively referred to as a downlink signal. The uplink physicalchannels and the uplink physical signals are collectively referred to asan uplink signal. The downlink physical channels and the uplink physicalchannels are collectively referred to as a physical channel The downlinkphysical signals and the uplink physical signals are collectivelyreferred to as a physical signal.

The BCH, the MCH, the UL-SCH, and the DL-SCH are transport channels. Achannel used in a Medium Access Control (MAC) layer is referred to as atransport channel. A unit of the transport channel used in the MAC layeris also referred to as a transport block (TB) or a MAC Protocol DataUnit (PDU). A Hybrid Automatic Repeat reQuest (HARQ) is controlled foreach transport block in the MAC layer. The transport block is a unit ofdata that the MAC layer delivers to the physical layer. In the physicallayer, the transport block is mapped to a codeword and subjected tocoding processing on a codeword-by-codeword basis.

The base station device 3 and the terminal device 1 exchange (transmitand/or receive) a signal in the higher layer. For example, the basestation device 3 and the terminal device 1 may transmit and/or receive,in a Radio Resource Control (RRC) layer, RRC signaling (also referred toas a Radio Resource Control message (RRC message) or Radio ResourceControl information (RRC information)). Furthermore, the base stationdevice 3 and the terminal device 1 may transmit and/or receive, in theMedium Access Control (MAC) layer, a MAC Control Element (CE). Here, theRRC signaling and/or the MAC CE is also referred to as higher layersignaling.

The PUSCH and the PDSCH are used for transmission of the RRC signalingand the MAC CE. Here, the RRC signaling transmitted from the basestation device 3 on the PDSCH may be signaling common to multipleterminal devices 1 in a cell. The RRC signaling transmitted from thebase station device 3 on the PDSCH may be signaling dedicated to acertain terminal device 1 (also referred to as dedicated signaling or UEspecific signaling). A cell-specific parameter may be transmitted byusing the signaling common to the multiple terminal devices 1 in thecell or the signaling dedicated to the certain terminal device 1. AUE-specific parameter may be transmitted by using the signalingdedicated to the certain terminal device 1.

The uplink grant includes a DCI format 0 and a DCI format 4. A PUSCHtransmission scheme corresponding to the DCI format 0 is single antennaport. A PUSCH transmission scheme corresponding to the DCI format 4 isclosed-loop spatial multiplexing.

The downlink grant includes a DCI format 1A and a DCI format 2. A PDSCHtransmission scheme corresponding to the DCI format 1A is single antennaport or transmit diversity. A PDSCH transmission scheme corresponding tothe DCI format 2 is closed-loop spatial multiplexing.

A PDCCH/EPDCCH including a DCI format used for scheduling a PDSCH/PUSCHin a certain serving cell is referred to as PDCCH/EPDCCH for the certainserving cell.

A DCI format used for scheduling a PDSCH/PUSCH in a certain serving cellis referred to as a DCI format for the certain serving cell. A payloadsize of the DCI format 0 for a certain serving cell is same as a payloadsize of the DCI format 1A for the same serving cell. The DCI format 0and the DCI format 1A include a flag indicating a type of the DCI format(0 or 1A). The DCI format 0 and/or the DCI format 1A is also referred toas a DCI format 0/1A.

Apart from the DCI format 0/1A, a different DCI format for a certainserving cell has a different payload size. Apart from the DCI format0/1A, the terminal device 1 can specify a DCI format, based on thepayload size of the DCI format. Different DCI formats for differentserving cells may have the same payload size. The terminal device 1 canspecify the DCI format, based on a Carrier Indicator Field (CIF) valueincluded in the DCI format. The CIF is a field to which a carrierindicator is mapped. The carrier indicator value indicates a servingcell to which the DCI format associated with the carrier indicatorcorresponds. The carrier indicator value is also referred to as a CIFvalue.

The PDCCH/EPDCCH for the primary cell is transmitted in the primarycell. The PDCCH/EPDCCH for the secondary cell is transmitted in theprimary cell, the same secondary cell, or a different secondary cell.

Based on the detection of a PDCCH/EPDCCH including a CIF in a certainserving cell, the terminal device 1 decodes a PDSCH in a serving cellindicated by a CIF value included in the decoded PDCCH/EPDCCH.

The terminal device 1 that is configured to monitor, in another servingcell, the PDCCH/EPDCCH corresponding to the serving cell and includingthe CIF monitors the PDCCH/EPDCCH including the CIF in another servingcell. The terminal device 1 that is configured to monitor, in anotherserving cell, the PDCCH/EPDCCH corresponding to the serving cell andincluding the CIF may not monitor the PDCCH/EPDCCH in the serving cell.

The terminal device 1 that is not configured to monitor, in anotherserving cell, the PDCCH/EPDCCH corresponding to the serving cell andincluding the CIF monitors the PDCCH/EPDCCH in the serving cell.

The monitoring of the PDCCH/EPDCCH including the CIF implies attemptingto decode the PDCCH or the EPDCCH in accordance with the DCI formatincluding the CIF.

The base station device 3 transmits, to the terminal device 1, aparameter (cif-Presence-r10) indicating whether the CIF is included inthe DCI format transmitted in the primary cell.

For each secondary cell, the base station device 3 transmits, to theterminal device 1, a parameter (CrossCarrierSchedulingConfig-r10)associated with cross carrier scheduling.

The parameter (CrossCarrierSchedulingConfig-r10) includes a parameter(schedulingCellInfo-r10) indicating whether the PDCCH/EPDCCHcorresponding to an associated secondary cell is transmitted in thesecondary cell or is transmitted in a different serving cell.

In a case where the parameter (schedulingCellInfo-r10) indicates thatthe PDCCH/EPDCCH corresponding to the associated secondary cell istransmitted in the secondary cell, the parameter(schedulingCellInfo-r10) includes the parameter (cif-Presence-r10)indicating whether or not the CIF is included in a DCI formattransmitted in the secondary cell.

In a case where the parameter (schedulingCellInfo-r10) indicates thatthe PDCCH/EPDCCH corresponding to the associated secondary cell istransmitted in another serving cell, the parameter(schedulingCellInfo-r10) includes a parameter (schedulingCellId)indicating in which serving cell the DCI format for the associatedsecondary cell is sent.

In the case where the parameter (schedulingCellInfo-r10) indicates thatthe PDCCH/EPDCCH corresponding to the associated secondary cell istransmitted in another serving cell, the base station device 3 maytransmit, to the terminal device 1, information indicating to which CIFvalue included in the PDCCH/EPDCCH in the another serving cell thesecondary cell corresponds.

FIG. 4 is a diagram illustrating an example of downlink signal mappingaccording to the present embodiment. A PDCCH region is indicated by aCFI included in the PCFICH. The PDCCH region includes multiple PDCCHcandidates. One PDCCH is transmitted by using one PDCCH candidate.

An EPDCCH region includes multiple EPDCCH candidates. One EPDCCH istransmitted by using one EPDCCH candidate. The EPDCCH region is alsoreferred to as an EPDCCH set or an EPDCCH-PRB set. The base stationdevice 3 transmits, to the terminal device 1, information indicating afrequency band constituting the EPDCCH set. The frequency bandconstituting the EPDCCH set is expressed by a PRB index. The PRB index,to which one EPDCCH set corresponds, may be non-contiguous. In onesubframe of one serving cell, two EPDCCH sets may be configured.

FIG. 5 is a diagram illustrating an example of a transmission process ofDownlink Control Information according to the present embodiment. (500)The base station device 3 derives CRC parity bits, based on DownlinkControl Information (DCI format), and attaches CRC parity bits scrambledwith the RNTI to the Downlink Control Information. (501) The basestation device 3 performs channel coding on the Downlink ControlInformation, to which the CRC parity bits scrambled with the RNTI areattached.

(502) The base station device 3 performs QPSK modulation on the DownlinkControl Information, which has been subjected to channel coding. (503)The base station device 3 maps a modulation symbol of the DownlinkControl Information to a resource element (the PDCCH candidate or theEPDCCH candidate).

The terminal device 1 monitors a set of PDCCH candidates and/or all setsof EPDCCH candidates in one subframe of the serving cell. The terminaldevice 1 may not monitor all PDCCH candidates and all EPDCCH candidatesin one subframe of the serving cell. The monitoring implies attemptingto decode each of the PDCCHs/EPDCCHs in the set of PDCCH candidates/setof EPDCCH candidates according to a monitored DCI format.

The base station device 3 selects, from the set of PDCCH candidatesand/or all sets of EPDCCH candidates monitored by the terminal device 1in one subframe of the serving cell, a PDCCH candidate/EPDCCH candidateto be used for PDCCH transmission to the terminal device 1.

The set of PDCCH candidates to be monitored and the set of EPDCCHcandidates to be monitored are also referred to as a search space.Multiple search spaces include multiple Common Search Spaces (CSSs) andmultiple User equipment-specific Search Spaces (USSs). The multiple CSSsinclude multiple PDCCH CSSs. The multiple USSs include multiple PDCCHUSSs and multiple EPDCCH USSs. One PDCCH USS is one set constituted bymultiple PDCCH candidates. One EPDCCH USS is one set constituted bymultiple EPDCCH candidates.

The PDCCH candidates included in the same PDCCH CSS are constituted bythe same number of Control Channel Elements (CCEs). The PDCCH candidatesincluded in the same PDCCH USS are constituted by the same number ofCCEs. The EPDCCH candidates included in the same EPDCCH USS areconstituted by the same number of Enhanced Control Channel Elements(ECCEs). The number of CCEs constituting a PDCCH candidate and thenumber of ECCEs constituting an EPDCCH candidate are referred to as anaggregation level L. The CCE is constituted by multiple resourceelements included in the PDCCH region. The ECCE is constituted bymultiple resource elements included in the EPDCCH set. The PDCCH USS andthe EPDCCH USS are defined for each aggregation level.

For each of the serving cells in which the PDCCH is monitored, one ormultiple CCEs corresponding to (a) PDCCH candidate(s) m included in aPDCCH USS Sk(L) corresponding to an aggregation level L in a subframe kis given by Expression (5), Expression (6), and Expression (7).

L{(Y _(k)+m′)mod floor(N _(CCE,k) /L)}+i   [Expression 5]

where i=0,1, . . . ,L−1

m′m+M ^((L)) ·n _(CI) where m=0,1, . . . ,M ^((L))−1   [Expression 6]

Y _(k)=(A·Y _(k−1))modD   [Expression 7]

where

Y _(l)−n _(RNTI)≠0, A=39827, D=6537, k=floor(n _(s)/2)

X mod Y is a function returning a remainder obtained by dividing X by Y.floor is a function returning a value obtained by truncating an inputvalue after the decimal point. NCCE,k is a total number of CCEs includedin the subframe k. m is an index of PDCCH candidates included in thePDCCH USS Sk(L). M(L) is the number of PDCCH candidates monitored in thePDCCH USS Sk(L). nCI is a CIF value. The PDCCH USS Sk(L) is defined foreach CIF value. The terminal device 1 monitors a PDCCH USS Sk (L)corresponding to a value to which the CIF included in the DCI format tobe monitored can be set. nRNTI is an RNTI value. In the presentembodiment, nRNTI is a C-RNTI value.

M(L) may be a value decided in advance for each aggregation level L. Forexample, for L=2, M(L) may be 6.

FIG. 6 is a diagram illustrating an example of PDCCH USSs in onesubframe k of one serving cell according to the present embodiment. ThePDCCH USSs in FIG. 6 are given by Expressions (5) and (6). In FIG. 6,the horizontal axis gives an index nCCE of CCEs included in one subframek of one serving cell. FIG. 6 includes a PDCCH USS 600 corresponding toa CIF value 0, a PDCCH USS 601 corresponding to a CIF value 1, and aPDCCH USS 602 corresponding to a CIF value 2. Bold squares with i arePDCCH candidates included in a PDCCH USS corresponding to a CIF value i.In FIG. 6, bold squares with 0 and 2 are PDCCH candidates included inboth the PDCCH USS 600 and the PDCCH USS 602. In FIG. 6, NCCE,k is 32, Lis 2, and Yk is 2. In FIG. 6, M(L) is 6 for each of the PDCCH USSs 600,601, and 602.

In FIG. 6, a PDCCH candidate m=M(L)−1 included in a PDCCH USScorresponding to a certain CIF value is adjacent to a PDCCH candidatem=0 included in a PDCCH USS corresponding to a CIF value that is greaterby one than the certain CIF value. That is, a PDCCH USS corresponding toa certain CIF value is adjacent to a PDCCH USS corresponding to a CIFvalue that is greater by one than the certain CIF value.

The number M(L) of PDCCH candidates included in the PDCCH USS monitoredby the terminal device 1 may be reduced based on a coefficient αc. Thenumber Mc(L) of PDCCH candidates reduced based on the coefficient αc maybe given by Expression (6). c is a CIF value. Reducing the number ofPDCCH candidates can reduce a load of a reception process by theterminal device 1.

M _(c) ^((L))=ceiling (α_(c) ·M ^((L)) where α_(c)∈{0, 0.33 0.661}  [Expression 8]

m′=m+M ^((L)) ·n _(CI) where m=0,1, . . . ,M _(c) ^((L))−1   [Expression9]

ceiling is a function returning a value obtained by rounding up an inputvalue to the whole number. The coefficient αc may be defined for eachaggregation level. The coefficient αc may be defined for each scheduledserving cell. The coefficient αc may be defined for each CIF value, towhich the PDCCH USS corresponds. The base station device 3 may transmitinformation/a parameter indicating the coefficient αc to the terminaldevice 1.

FIG. 7 is a diagram illustrating an example of PDCCH USSs in onesubframe k of one serving cell according to the present embodiment. ThePDCCH USSs in FIG. 7 are given by Expressions (5), (6), and (7). In FIG.7, the horizontal axis gives an index nCCE of CCEs included in onesubframe k of one serving cell. FIG. 7 includes a PDCCH USS 700corresponding to a CIF value 0 and a PDCCH USS 702 corresponding to aCIF value 2. Bold squares with i are PDCCH candidates included in aPDCCH USS corresponding to a CIF value i. In FIG. 7, bold squares with 0and 2 are PDCCH candidates included in both the PDCCH USS 700 and thePDCCH USS 702. In FIG. 7, NCCE,k is 32, L is 2, and Yk is 2. For thePDCCH USS 700, α0 is 0.66 and M0(L) is 4. For the PDCCH USS 701, α1 is 0and M1(L) is 0. For the PDCCH USS 702, α2 is 1 and M2(L) is 6.

In FIG. 7, a CCE, to which a PDCCH candidate m=0 included in a PDCCH USScorresponding to a certain CIF value corresponds, does not depend on avalue of the coefficient αc. As a result, a process for monitoring bythe terminal device 1 can be simplified.

In FIG. 7, PDCCH candidates monitored by the terminal device 1 arereduced; however, PDCCH candidates included in multiple PDCCH USSs stillexist. Due to the PDCCH candidates included in the multiple PDCCH USSs,scheduling of the PDCCH by the base station device 3 is limited.

Expression (10) may be used instead of Expression (9). In Expression(10), Mc(L) corresponding to a value that cannot be taken as a CIFincluded in a DCI format monitored on a serving cell including the PDCCHUSS is 0, and M−1(L) is 0.

$\begin{matrix}{{m^{\prime} = {m_{n_{CI}} + {\sum\limits_{x = {- 1}}^{n_{CI} - 1}M_{x}^{(L)}}}}{{{{where}\mspace{14mu} m_{n_{CI}}} = 0},1,\ldots \mspace{14mu},{{M_{n_{CI}}^{(L)} - {1.\mspace{14mu} M_{- 1}^{(L)}}} = 0}}} & \left\lbrack {{Expression}\mspace{14mu} 10} \right\rbrack\end{matrix}$

FIG. 8 is a diagram illustrating an example of PDCCH USSs in onesubframe k of one serving cell according to the present embodiment. ThePDCCH USSs in FIG. 8 are given by Expressions (5), (8), and (10). InFIG. 8, the horizontal axis gives an index nCCE of CCEs included in onesubframe k of one serving cell. FIG. 8 includes a PDCCH USS 800corresponding to a CIF value 0 and a PDCCH USS 802 corresponding to aCIF value 2. Bold squares with i are PDCCH candidates included in aPDCCH USS corresponding to a CIF value i. In FIG. 8, NCCE,k is 32, L is2, and Yk is 2. For the PDCCH USS 800, α0 is 0.66 and M0(L) is 4. Forthe PDCCH USS 801, α1 is 0 and M1(L) is 0. For the PDCCH USS 802, α2 is1 and M2(L) is 6.

In FIG. 8, a CCE to, which a PDCCH candidate m=0 included in a PDCCH USScorresponding to a certain CIF value corresponds, is given based on avalue of the coefficient αc and an Mc(L) value. This can reduce theprobability that a certain PDCCH candidate is simultaneously included inmultiple PDCCH USSs.

In a case that the terminal device 1 is not configured to monitor thePDCCH including the CIF in the serving cell, a value of m′ inExpressions (6), (9), and (10) may be 0.

For a serving cell in which the EPDCCH is monitored, one or multipleECCEs corresponding to (an) EPDCCH candidate(s) m included in an EPDCCHUSS ESk(L) corresponding to an aggregation level L in an EPDCCH set p ina subframe k is given by Expression (11) and Expression (12).

$\begin{matrix}{{{L\left\{ {\left( {Y_{p,k} + {{floor}\left( \frac{m_{p} \cdot N_{{ECCE},p,k}}{L \cdot M_{p}^{(L)}} \right)} + b} \right){mod}\mspace{11mu} {{floor}\left( {N_{{CCE},p,k}/L} \right)}} \right\}} + {i\mspace{14mu} {where}}}\text{}\mspace{20mu} {{i = 0},1,\ldots \mspace{14mu},{L - 1},{m_{p} = 0},1,\ldots \mspace{14mu},{M_{p}^{(L)} - 1}}} & \left\lbrack {{Expression}\mspace{14mu} 11} \right\rbrack \\{\mspace{79mu} {{Y_{p,k} = {\left( {A_{p} \cdot Y_{p,{k - 1}}} \right){mod}\mspace{11mu} D\mspace{14mu} {where}}}\text{}\mspace{20mu} {{Y_{p,{- 1}} = {n_{RNTI} \neq 0}},{A_{0} = 39827},{A_{1} = 39829},\mspace{20mu} {D = 65537},{k = {{floor}\left( {n_{s}/2} \right)}}}}} & \left\lbrack {{Expression}\mspace{14mu} 12} \right\rbrack\end{matrix}$

NECCE,p,k is a total number of ECCEs included in the EPDCCH set p insubframe k. mp is an index of the EPDCCH candidates included in theEPDCCH USS ESk(L). b is a CIF value. Mp(L) is the number of EPDCCHcandidates monitored in the EPDCCH USS ESk(L). The EPDCCH USS ESk(L) isdefined for each CIF value. The terminal device 1 monitors an EPDCCH USSSk (L) corresponding to a value to which a CIF included in the DCIformat to be monitored can be set. nRNTI is a value of the RNTI. In thepresent embodiment, nRNTI is a value of the C-RNTI.

Mp(L) may be given based on the aggregation level L, the number of PRBsincluded in the EPDCCH set, the number of EPDCCH sets configured in onesubframe in the serving cell, and the like. In FIG. 9 to FIG. 12, Mp(L)is 6. It is noted that in FIG. 10 to FIG. 12, the number of EPDCCHcandidates actually monitored in the EPDCCH USS ESk(L) is subtractedfrom Mp(L).

FIG. 9 is a diagram illustrating an example of EPDCCH USSs in one EPDCCHset p in one subframe k of one serving cell according to the presentembodiment. The EPDCCH USSs in FIG. 9 are given by Expression (11). InFIG. 9, the horizontal axis gives an index nECCE of ECCEs included inone EPDCCH set p in one subframe k of one serving cell. FIG. 6 includesan EPDCCH USS 900 corresponding to a CIF value 0 and an EPDCCH USS 901corresponding to a CIF value 1. Bold squares with i are EPDCCHcandidates included in an EPDCCH USS corresponding to a CIF value i. InFIG. 9, NECCE,p,k is 32, L is 2, and Yp,k is 0. In FIG. 9, Mp(L) is 6for each of the EPDCCH USSs 900 and 901.

In FIG. 9, an EPDCCH candidate mp=x included in an EPDCCH USScorresponding to a certain CIF value is adjacent to an EPDCCH candidatemp=x included in an EPDCCH USS corresponding to a CIF value that isgreater by one than the certain CIF value.

The number Mp(L) of EPDCCH candidates included in the EPDCCH USSmonitored by the terminal device 1 may be reduced based on a coefficientαp,c. The number Mp,c(L) of EPDCCH candidates reduced based on thecoefficient αp,c may be given by Expression (13). c is a CIF value. Byreducing the number of EPDCCH candidates, the load of the receptionprocess by the terminal device 1 can be reduced.

M _(p,c) ^((L))=ceiling (α_(p,c) ·M _(p) ^((L)) where α_(p,c)∈{0, 0.330.66 1}[Expression 13]

The coefficient αp,c may be defined for each aggregation level and foreach EPDCCH set. The coefficient αp,c may be defined for each scheduledserving cell. The coefficient αp,c may be defined for each CIF value, towhich the EPDCCH USS corresponds. The base station device 3 may transmitinformation/a parameter indicating the coefficient αp,c to the terminaldevice 1.

The terminal device 1 may use, in Expression (11), Mp,c(L) instead ofMp(L). Expression (14) is obtained by replacing Mp(L) in Expression (11)with Mp,c(L).

$\begin{matrix}{{{L\left\{ {\left( {Y_{p,k} + {{floor}\left( \frac{m_{p} \cdot N_{{ECCE},p,k}}{L \cdot M_{p,c}^{(L)}} \right)} + b} \right){mod}\mspace{11mu} {{floor}\left( {N_{{CCE},p,k}/L} \right)}} \right\}} + {i\mspace{14mu} {where}}}\text{}\mspace{20mu} {{i = 0},1,\ldots \mspace{14mu},{L - 1},{m_{p} = 0},1,\ldots \mspace{14mu},{M_{p,c}^{(L)} - 1}}} & \left\lbrack {{Expression}\mspace{14mu} 14} \right\rbrack\end{matrix}$

FIG. 10 is a diagram illustrating an example of EPDCCH USSs in oneEPDCCH set p in one subframe k of one serving cell according to thepresent embodiment. The EPDCCH USSs in FIG. 10 are given by Expression(14). In FIG. 10, the horizontal axis gives an index nECCE of ECCEsincluded in one EPDCCH set p in one subframe k of one serving cell. FIG.10 includes an EPDCCH USS 1000 corresponding to a CIF value 0 and anEPDCCH USS 1001 corresponding to a CIF value 1. Bold squares with i areEPDCCH candidates included in the EPDCCH USS corresponding to a CIFvalue i. In FIG. 10, bold squares with 0 and 1 are EPDCCH candidatesincluded in both the EPDCCH USS 1000 and the EPDCCH USS 1002. In FIG.10, NECCE,k is 32, L is 2, and Yp,k is 0. For the EPDCCH USS 1000, αp,0is 1 and Mp,0(L) is 6. For the EPDCCH USS 1001, αp,1 is 0.66 and Mp,1(L)is 4.

In FIG. 10, an ECCE, to which an EPDCCH candidate mp=0 included in anEPDCCH USS corresponding to a certain CIF value corresponds, does notdepend on a value of the coefficient αp,c. In FIG. 10, an ECCE, to whichan EPDCCH candidate mp≠0 included in an EPDCCH USS corresponding to acertain CIF value corresponds, depends on the value of the coefficientαp,c.

In FIG. 10, PDCCH candidates monitored by the terminal device 1 arereduced; however, the possibility of an existence of EPDCCH candidatesincluded in multiple EPDCCH USSs increases. Due to the EPDCCH candidatesincluded in the multiple EPDCCH USSs, scheduling of the EPDCCH by thebase station device 3 is limited.

The terminal device 1 may not use Mp,c(L) instead of Mp(L), even in acase that Mp(L) is reduced by αp,c. Expression (15) is obtained bychanging the value of mp in Expression (11) from 0 to Mp,c(L). However,Mp(L) input in the floor function of Expression (15) is not changed toMp,c(L).

$\begin{matrix}{{{L\left\{ {\left( {Y_{p,k} + {{floor}\left( \frac{m_{p} \cdot N_{{ECCE},p,k}}{L \cdot M_{p}^{(L)}} \right)} + b} \right){mod}\mspace{11mu} {{floor}\left( {N_{{CCE},p,k}/L} \right)}} \right\}} + {i\mspace{14mu} {where}}}\text{}\mspace{20mu} {{i = 0},1,\ldots \mspace{14mu},{L - 1},{m_{p} = 0},1,\ldots \mspace{14mu},{M_{p,c}^{(L)} - 1}}} & \left\lbrack {{Expression}\mspace{14mu} 15} \right\rbrack\end{matrix}$

FIG. 11 is a diagram illustrating an example of EPDCCH USSs in oneEPDCCH set p in one subframe k of one serving cell according to thepresent embodiment. The EPDCCH USSs in FIG. 11 are given by Expression(15). In FIG. 11, the horizontal axis gives an index nECCE of ECCEsincluded in one EPDCCH set p in one subframe k of one serving cell. FIG.11 includes an EPDCCH USS 1100 corresponding to a CIF value 0 and anEPDCCH USS 1101 corresponding to a CIF value 1. Bold squares with i areEPDCCH candidates included in the EPDCCH USS corresponding to a CIFvalue i. In FIG. 11, NECCE,k is 32, L is 2, and Yp,k is 0. For theEPDCCH USS 1100, αp,0 is 1 and Mp,0(L) is 6. For the EPDCCH USS 1101,αp,1 is 0.66 and Mp,1(L) is 4.

In FIG. 11, an ECCE, to which a PDCCH candidate mp=x included in anEPDCCH USS corresponding to a certain CIF value corresponds, does notdepend on the value of the coefficient αp,c. In FIG. 11, an EPDCCHcandidate mp=x included in an EPDCCH USS corresponding to a certain CIFvalue is adjacent to an EPDCCH candidate mp=x included in an EPDCCH USScorresponding to a CIF value that is greater by one than the certain CIFvalue.

The EPDCCH USS 1101 in FIG. 11 is obtained by reducing a part of theEPDCCH candidates included in the EPDCCH USS 1001 in FIG. 10. Whenreducing the EPDCCH USS 1001 in FIG. 10, the EPDCCH candidates arereduced starting from the one having a larger index. As a result, theindex of ECCEs corresponding to multiple EPDCCH candidates included inthe EPDCCH USS 1101 in FIG. 11 becomes biased, and thus, frequencyselection diversity effect from frequency-selective scheduling of theEPDCCH is limited.

Thus, mp in expression (15) may be replaced with m′p. Expression (15) isobtained by replacing mp in Expression (15) with m′p. The values of mpin Expression (15) are values continuous from 0 to Mp,c(L), while m′p inExpression (15) represents non-consecutive values starting from 0 andnot exceeding Mp,c(L)−1. The values of m′p are based on αp,c or Mp,c(L)calculated from αp,c. For example, m′p is given by Expression (17) orExpression (18).

$\begin{matrix}{{{L\left\{ {\left( {Y_{p,k} + {{floor}\left( \frac{m_{p}^{\prime} \cdot N_{{ECCE},p,k}}{L \cdot M_{p}^{(L)}} \right)} + b} \right){mod}\mspace{11mu} {{floor}\left( {N_{{CCE},p,k}/L} \right)}} \right\}} + i}\mspace{20mu} {{{{where}\mspace{14mu} i} = 0},1,\ldots \mspace{14mu},{L - 1}}} & \left\lbrack {{Expression}\mspace{14mu} 16} \right\rbrack \\{\mspace{20mu} {{m_{p}^{\prime} = {{{floor}\left( \frac{M^{(L)} \cdot m_{p,c}}{M_{p,c}^{(L)}} \right)}\mspace{14mu} {where}}}\text{}\mspace{20mu} {{m_{p,c} = 0},1,\ldots \mspace{14mu},{M_{p,c}^{(L)} - 1}}}} & \left\lbrack {{Expression}\mspace{14mu} 17} \right\rbrack \\{\mspace{20mu} {{m_{p}^{\prime} = {{{floor}\left( \frac{m_{p,c}}{\alpha_{p,c}} \right)}\mspace{14mu} {where}}}\text{}\mspace{20mu} {{m_{p,c} = 0},1,\ldots \mspace{14mu},{M_{p,c}^{(L)} - 1}}}} & \left\lbrack {{Expression}\mspace{14mu} 18} \right\rbrack\end{matrix}$

FIG. 12 is a diagram illustrating an example of EPDCCH USSs in oneEPDCCH set p in one subframe k of one serving cell according to thepresent embodiment. The EPDCCH USSs in FIG. 12 are given by Expression(16) and Expression (18). In FIG. 12, the horizontal axis gives an indexnECCE of ECCEs included in one EPDCCH set p in one subframe k of oneserving cell. FIG. 12 includes an EPDCCH USS 1200 corresponding to a CIFvalue 0 and an EPDCCH USS 1201 corresponding to a CIF value 1. Boldsquares with i are EPDCCH candidates included in the EPDCCH USScorresponding to a CIF value i. In FIG. 12, NECCE,k is 32, L is 2, andYp,k is 0. For the EPDCCH USS 1200, αp,0 is 1 and Mp,0(L) is 6. For theEPDCCH USS 1201, αp,1 is 0.66 and Mp,1(L) is 4.

The EPDCCH USS 1201 in FIG. 12 is obtained by reducing a part of theEPDCCH candidates included in the EPDCCH USS 1001 in FIG. 10. Whenreducing the EPDCCH USS 1001 in FIG. 10, the index mp of the EPDCCHcandidates is discontinuously reduced. As a result, the index of ECCEscorresponding to multiple EPDCCH candidates included in the EPDCCH USS1201 in FIG. 12 does not become biased, and thus, the frequencyselection diversity effect from the frequency-selective scheduling ofthe EPDCCH can be easily obtained.

In a case that the terminal device 1 is not configured to monitor theEPDCCH including the CIF on the serving cell, a value of b inExpressions (11), (14), (15), and (16) may be 0.

A correspondence between a DCI format and a USS according to the presentembodiment will be described below.

A PDCCH used for transmitting a DCI format including a certain CIF valuemay be transmitted in a USS corresponding to the certain CIF value. In acase that different DCI formats have the same payload size, the PDCCHmay be transmitted in any of different USSs corresponding to each ofdifferent CIF values included in the different DCI formats. The casethat different DCI formats have the same payload size is the case thatthe same payload size correspond to multiple CIF values. In the casethat different DCI formats have the same payload size, the load of thereception process of the terminal device 1 increases only slightly, evenin a case that the different DCI formats having different CIF valuesshare the USS.

A DCI format including a CIF value corresponding to a certain servingcell is referred to as a DCI format for a certain serving cell. The basestation device 3 may transmit, to the terminal device 1, information/aparameter for instructing deactivation of monitoring of a DCI format0/1A for a certain serving cell.

In a case that the monitoring of the DCI format 0/1A for a certainserving cell is deactivated, the terminal device 1 does not monitor theDCI format 0/1A for the certain serving cell in a USS based on a CIFvalue, to which the certain serving cell corresponds.

In the case that the monitoring of the DCI format 0/1A for a certainserving cell is deactivated, the terminal device 1 monitors the DCIformat 0/1A for the certain serving cell in the USS based on the CIFvalue, to which the certain serving cell corresponds.

Regardless of whether the monitoring of the DCI format 0/1A for acertain serving cell is deactivated, the terminal device 1 monitors aDCI format Y for the certain serving cell in the USS based on the CIFvalue, to which the certain serving cell corresponds. Here, the DCIformat Y is a DCI format other than the DCI format 0/1A.

FIG. 13 is a diagram illustrating a correspondence between a DCI formatand a USS in a case that monitoring of a DCI format 0/1A for a servingcell c1 corresponding to a CIF value 1 is not deactivated, according tothe present embodiment.

FIG. 14 is a diagram illustrating a correspondence between the DCIformat and the USS in a case that the monitoring of the DCI format 0/1Afor the serving cell c1 corresponding to the CIF value 1 is deactivated,according to the present embodiment.

FIG. 15 is a diagram illustrating a correspondence between the DCIformat and the USS in the case that the monitoring of the DCI format0/1A for the serving cell c1 corresponding to the CIF value 1 isdeactivated, according to the present embodiment.

In FIG. 13, FIG. 14, and FIG. 15, a payload size of a DCI format X for aserving cell c0 (1301) is the same as a payload size of the DCI format0/1A for the serving cell c1 (1302).

In FIG. 13, FIG. 14, and FIG. 15, the payload size of the DCI format Xof the serving cell c0 (1301) is the same as the payload size of the DCIformat 0/1A for the serving cell c1 (1302). In FIG. 13, FIG. 14, andFIG. 15, the DCI format X may include the DCI format 0/1A and/or a DCIformat other than the DCI format 0/1A. In FIG. 13, FIG. 14, and FIG. 15,regardless of whether the monitoring of the DCI format 0/1A for theserving cell c1 is deactivated, the terminal device 1 considers thatthere is a possibility that the DCI format X for the serving cell c0(1301) is transmitted in the PDCCH candidates/EPDCCH candidates in a USScorresponding to a CIF value 0 on the serving cell c0 (1303). In a casethat the terminal device 1 considers that there is a possibility of theDCI format is transmitted in the PDCCH candidates/EPDCCH candidates inthe USS, the terminal device 1 attempts to decode a PDCCH in the PDCCHcandidates/EPDCCH candidates in the USS, in accordance with the DCIformat.

In FIG. 13, the terminal device 1 considers that there is a possibilitythat the DCI format X for the serving cell c0 (1301) is transmitted inthe PDCCH candidates/EPDCCH candidates in any of the USS correspondingto the CIF value 0 on the serving cell c0 (1303) and a USS correspondingto a CIF value 1 on the serving cell c0 (1304). In FIG. 13, the terminaldevice 1 considers that there is a possibility that the DCI format 0/1Afor the serving cell c1 (1302) is transmitted in the PDCCHcandidates/EPDCCH candidates in any of the USS corresponding to the CIFvalue 0 on the serving cell c0 (1303) and the USS corresponding to theCIF value 1 in the serving cell c0 (1304).

In FIG. 14, the terminal device 1 considers that there is a possibilitythat the DCI format X for the serving cell c0 (1301) is transmitted inthe PDCCH candidates/EPDCCH candidates in the USS corresponding to theCIF value 0 on the serving cell c0 (1303). In FIG. 13, the terminaldevice 1 considers that there is no possibility that the DCI format 0/1Afor the serving cell c1 (1302) is transmitted in any of the USScorresponding to the CIF value 0 on the serving cell c0 (1303) and theUSS corresponding to the CIF value 1 on the serving cell c0 (1304).

In FIG. 14, in a case that the monitoring of the DCI format 0/1A for theserving cell c1 (1302) is deactivated, the monitoring of the DCI formatX (1301) having the same payload size as the payload size of the DCIformat 0/1A (1302) is also deactivated in a USS based on the CIF value,to which the serving cell c1 corresponds. This can further reduce theload of the reception process by the terminal device 1.

In FIG. 15, the terminal device 1 considers that there is a possibilitythat the DCI format X for the serving cell c0 (1301) is transmitted inthe PDCCH candidates/EPDCCH candidates in the USS corresponding to theCIF value 0 on the serving cell c0 (1303). In FIG. 15, the terminaldevice 1 considers that there is a possibility that the DCI format 0/1Afor the serving cell c1 (1302) is transmitted in the PDCCHcandidates/EPDCCH candidates in the USS corresponding to the CIF value 0on the serving cell c0 (1303).

In FIG. 15, in the case that the monitoring of the DCI format 0/1A forthe serving cell c1 (1302) is deactivated, the monitoring of the DCIformat X (1301) having the same payload size as the payload size of theDCI format 0/1A (1302) is also deactivated in the USS based on the CIFvalue, to which the serving cell c1 corresponds. This can further reducethe load of the reception process by the terminal device 1.

In FIG. 15, regardless of the monitoring of the DCI format 0/1A for theserving cell c1 (1302) being deactivated, it is considered that there isa possibility that the DCI format 0/1A for the serving cell c1 (1302) istransmitted in the PDCCH candidates/EPDCCH candidates in the USScorresponding to the CIF value 0 on the serving cell c0 (1303). As aresult, while the load of the reception process by the terminal device 1is slightly increased, the degree of freedom in scheduling of the PDCCHincluding the DCI format in the base station device 3 is largelyimproved.

That is, the base station device 3 may transmit, to the terminal device1, information/a parameter for instructing deactivation of themonitoring of the DCI format 0/1A for a certain serving cell in a USSbased on a CIF value corresponding to the certain serving cell.

Structures of devices according to the present embodiment will bedescribed below.

FIG. 16 is a schematic block diagram illustrating a constitution of theterminal device 1 according to the present embodiment. As illustrated,the terminal device 1 is configured to include a radio transmissionand/or reception unit 10 and a higher layer processing unit 14. Theradio transmission and/or reception unit 10 is configured to include anantenna unit 11, a Radio Frequency (RF) unit 12, and a baseband unit 13.The higher layer processing unit 14 is configured to include a mediumaccess control layer processing unit 15 and a radio resource controllayer processing unit 16. The radio transmission and/or reception unit10 is also referred to as a transmission unit, a reception unit or aphysical layer processing unit.

The higher layer processing unit 14 outputs uplink data (transportblock) generated by a user operation or the like, to the radiotransmission and/or reception unit 10. The higher layer processing unit14 performs processing of the Medium Access Control (MAC) layer, thePacket Data Convergence Protocol (PDCP) layer, the Radio Link Control(RLC) layer, and the Radio Resource Control (RRC) layer.

The medium access control layer processing unit 15 included in thehigher layer processing unit 14 performs processing of the Medium AccessControl layer. The medium access control layer processing unit 15controls transmission of a scheduling request, based on various types ofconfiguration information/parameters managed by the radio resourcecontrol layer processing unit 16.

The radio resource control layer processing unit 16 included in thehigher layer processing unit 14 performs processing of the RadioResource Control layer. The radio resource control layer processing unit16 manages the various types of configuration information/parameters ofthe terminal device 1. The radio resource control layer processing unit16 sets the various types of configuration information/parameters, basedon higher layer signaling received from the base station device 3. Thatis, the radio resource control layer processing unit 16 sets the varioustypes of configuration information/parameters, based on informationindicating the various types of configuration information/parametersreceived from the base station device 3.

The radio transmission and/or reception unit 10 performs processing ofthe physical layer, such as modulation, demodulation, coding, anddecoding. The radio transmission and/or reception unit 10 demultiplexes,demodulates, and decodes a signal received from the base station device3, and outputs the information resulting from the decoding to the higherlayer processing unit 14. The radio transmission and/or reception unit10 modulates and codes data to generate a transmit signal, and transmitsthe transmit signal to the base station device 3.

The RF unit 12 converts (down-converts) a signal received via theantenna unit 11 into a baseband signal by orthogonal demodulation andremoves unnecessary frequency components. The RF unit 12 outputs theprocessed analog signal to the baseband unit.

The baseband unit 13 converts the analog signal input from the RF unit12 into a digital signal. The baseband unit 13 removes a portioncorresponding to a Cyclic Prefix (CP) from the digital signal resultingfrom the conversion, performs Fast Fourier Transform (FFT) on the signalfrom which the CP has been removed, and extracts a signal in thefrequency domain.

The baseband unit 13 performs Inverse Fast Fourier Transform (IFFT) ondata, generates an SC-FDMA symbol, attaches a CP to the generatedSC-FDMA symbol, generates a baseband digital signal, and converts thebaseband digital signal into an analog signal. The baseband unit 13outputs the analog signal resulting from the conversion, to the RF unit12.

The RF unit 12 removes unnecessary frequency components from the analogsignal input from the baseband unit 13 using a low-pass filter,up-converts the analog signal into a signal of a carrier frequency, andtransmits the final result via the antenna unit 11. Furthermore, the RFunit 12 amplifies power. Furthermore, the RF unit 12 may have a functionof controlling transmit power. The RF unit 12 is also referred to as atransmit power control unit.

FIG. 17 is a schematic block diagram illustrating a constitution of thebase station device 3 according to the present embodiment. Asillustrated, the base station device 3 is configured to include a radiotransmission and/or reception unit 30 and a higher layer processing unit34. The radio transmission and/or reception unit 30 is configured toinclude an antenna unit 31, an RF unit 32, and a baseband unit 33. Thehigher layer processing unit 34 is configured to include a medium accesscontrol layer processing unit 35 and a radio resource control layerprocessing unit 36. The radio transmission and/or reception unit 30 isalso referred to as a transmission unit, a reception unit or a physicallayer processing unit.

The higher layer processing unit 34 performs processing of the MediumAccess Control (MAC) layer, the Packet Data Convergence Protocol (PDCP)layer, the Radio Link Control (RLC) layer, and the Radio ResourceControl (RRC) layer.

The medium access control layer processing unit 35 included in thehigher layer processing unit 34 performs processing of the Medium AccessControl layer. The medium access control layer processing unit 35performs processing associated with a scheduling request, based onvarious types of configuration information/parameters managed by theradio resource control layer processing unit 36.

The radio resource control layer processing unit 36 included in thehigher layer processing unit 34 performs processing of the RadioResource Control layer. The radio resource control layer processing unit36 generates, or acquires from a higher node, downlink data (transportblock) arranged on a physical downlink shared channel, systeminformation, an RRC message, a MAC Control Element (CE), and the like,and outputs the generated or acquired data to the radio transmissionand/or reception unit 30. Furthermore, the radio resource control layerprocessing unit 36 manages various types of configurationinformation/parameters for each of the terminal devices 1. The radioresource control layer processing unit 36 may set various types ofconfiguration information/parameters for each of the terminal devices 1via the higher layer signaling. In other words, the radio resourcecontrol layer processing unit 36 transmits/broadcasts informationindicating various types of configuration information/parameters.

The functionality of the radio transmission and/or reception unit 30 issimilar to that of the radio transmission and/or reception unit 10, andhence description thereof is omitted.

Each of the units having the reference signs 10 to 16 included in theterminal device 1 may be configured as a circuit. Each of the unitshaving the reference signs 30 to 36 included in the base station device3 may be configured as a circuit.

Various aspects of the terminal device 1 and the base station device 3according to the present embodiment will be described below.

(1) In a first aspect of the present embodiment, a terminal device 1includes a reception unit 10 configured to: decode, based on a detectionof a first PDCCH including a first DCI format including a first value ofa CIF on a first serving cell, a first PDSCH in the first serving cell;and decode, based on a detection of a second PDCCH including a secondDCI format including a second value of a CIF on the first serving cell,a second PDSCH in a second serving cell. In a case that monitoring ofthe second DCI format in the first serving cell is not deactivated andthat a size of the first DCI format and a size of the second DCI formatare the same, the reception unit 10 considers that there is apossibility that the first PDCCH including the first DCI format istransmitted in a USS given based on the second value. In a case thatmonitoring of the second DCI format in the first serving cell isdeactivated and that the size of the first DCI format and the size ofthe second DCI format are the same, the reception unit 10 considers thatthere is no possibility that the first PDCCH including the first DCIformat is transmitted in the USS given based on the second value. Here,the first DCI format may include a DCI format 0, a DCI format 1A, and/ora DCI format other than the DCI format 0/1A. Here, the second DCI formatmay include the DCI format 0 and/or the DCI format 1A.

(2) In the first aspect of the present embodiment, Cyclic RedundancyCheck (CRC) parity bits scrambled with a Cell-Radio Network TemporaryIdentifier (C-RNTI) are attached to the first DCI format and the secondDCI format.

(3) In the first aspect of the present embodiment, in the case that themonitoring of the second DCI format on the first serving cell isdeactivated and that the size of the first DCI format and the size ofthe second DCI format are the same, the reception unit 10 considers thatthere is a possibility of the second PDCCH including the second DCIformat being transmitted in a USS determined according to the firstvalue.

(4) In the first aspect of the present embodiment, in the case that themonitoring of the second DCI format on the first serving cell isdeactivated, the reception unit 10 considers that there is nopossibility of the second PDCCH including the second DCI format beingtransmitted in the USS determined according to the second value.

(6) In a second aspect of the present embodiment, a base station device3 includes a transmission unit 30 configured to: schedule, by using afirst PDCCH including a first DCI format including a first value of CIFon a first serving cell, a first PDSCH in the first serving cell; andschedule, by using a second PDCCH including a second DCI formatincluding a second value of a CIF on the first serving cell, a secondPDSCH in a second serving cell. In a case that monitoring of the secondDCI format in the first serving cell is not deactivated and that a sizeof the first DCI format and a size of the second DCI format are thesame, the transmission unit 30 selects, from a USS given based on thefirst value and a USS given based on the second value, a resource to betransmitted by the first PDCCH including the first DCI format. In a casethat the monitoring of the second DCI format in the first serving cellis deactivated and that the size of the first DCI format and the size ofthe second DCI format are the same, the transmission unit 30 selects,from the USS given based on the first value, a resource to betransmitted by the first PDCCH including the first DCI format. Here, thefirst DCI format may include a DCI format 0, a DCI format 1A, and/or aDCI format other than the DCI format 0/1A. Here, the second DCI formatmay include the DCI format 0 and/or the DCI format 1A.

(7) In the second aspect of the present embodiment, Cyclic RedundancyCheck (CRC) parity bits scrambled with a Cell-Radio Network TemporaryIdentifier (C-RNTI) are attached to the first DCI format and the secondDCI format.

(8) In the second aspect of the present embodiment, in the case that themonitoring of the second DCI format on the first serving cell isdeactivated and that the size of the first DCI format and the size ofthe second DCI format are the same, the transmission unit 30 does notselect, from the USS given based on the second value, a resource fortransmitting the first PDCCH including the first DCI format.

(9) In the second aspect of the present embodiment, in the case that themonitoring of the second DCI format on the first serving cell isdeactivated and that the size of the first DCI format and the size ofthe second DCI format are the same, the transmission unit 30 selects,from the USS given based on the first value, a resource for transmittingthe second PDCCH including the second DCI format.

(10) In the second aspect of the present embodiment, in the case thatthe monitoring of the second DCI format on the first serving cell isdeactivated, the transmission unit 30 does not select a resource fortransmitting the second PDCCH including the second DCI format in the USSgiven based on the second value.

(11) In a third aspect of the present embodiment, a terminal device 1includes a reception unit 10 configured to: attempt to decode, in afirst User Equipment-specific Search Space (USS) on a first servingcell, a Physical Downlink Control Channel (PDCCH) for the first servingcell; and attempt to decode, in a second USS on any one of the firstserving cell or a second serving cell, a PDCCH for the second servingcell. The number of PDCCH candidates included in the first USS is givenbased on a first parameter. In a case that the reception unit 10attempts to decode the PDCCH for the second serving cell in the secondUSS on the first serving cell, the number of PDCCH candidates includedin the second USS is given based on the first parameter. In a case thatthe reception unit 10 attempts to decode the PDCCH for the secondserving cell in the second USS on the second serving cell, the number ofPDCCH candidates included in the second USS is given based on a secondparameter different from the first parameter.

(12) In a fourth aspect of the present embodiment, a terminal device 1includes a reception unit 10 configured to: attempt to decode, in afirst User Equipment-specific Search Space (USS) on a first servingcell, a Physical Downlink Control Channel (PDCCH) for the first servingcell; and attempt to decode, in a second USS on the first serving cell,a PDCCH for a second serving cell. The number of PDCCH candidatesincluded in the first USS is determined according to a first parameter.The number of PDCCH candidates included in the second USS is determinedaccording to a second parameter different from the first parameter.

(11) In a fifth aspect of the present embodiment, a base station device3 includes a transmission unit 30 configured to: transmit, in a firstUser Equipment-specific Search Space (USS) on a first serving cell, aPhysical Downlink Control Channel (PDCCH) for the first serving cell;and transmit, in a second USS on any one of the first serving cell and asecond serving cell, a PDCCH for the second serving cell. The number ofPDCCH candidates included in the first USS is given based on a firstparameter. In a case that the transmission unit 30 transmits the PDCCHfor the second serving cell in the second USS on the first serving cell,the number of PDCCH candidates included in the second USS is given basedon the first parameter. In a case that the transmission unit 30transmits the PDCCH for the second serving cell in the second USS on thesecond serving cell, the number of PDCCH candidates included in thesecond USS is given based on a second parameter different from the firstparameter.

(12) In a sixth aspect of the present embodiment, a base station device3 includes a transmission unit 30 configured to: transmit, in a firstUser Equipment-specific Search Space (USS) on a first serving cell, aPhysical Downlink Control Channel (PDCCH) for the first serving cell;and transmit, in a second USS on the first serving cell, a decode of aPDCCH for a second serving cell. The number of PDCCH candidates includedin the first USS is determined according to a first parameter. Thenumber of PDCCH candidates included in the second USS is determinedaccording to a second parameter different from the first parameter.

Consequently, the terminal device and the base station device canefficiently communicate with each other by using a downlink channel.

The base station device 3 according to the present invention can also berealized as an aggregation (a device group) constituted of multipledevices. Each of the devices constituting such a device group mayinclude some or all portions of each function or each functional blockof the base station device 3 according to the above-describedembodiment. The device group may include each general function or eachfunctional block of the base station device 3. Furthermore, the terminaldevice 1 according to the above-described embodiment can alsocommunicate with the base station device as the aggregation.

Furthermore, the base station device 3 according to the above-describedembodiment may serve as an Evolved Universal Terrestrial Radio AccessNetwork (EUTRAN). Furthermore, the base station device 3 according tothe above-described embodiment may have some or all portions of thefunctions of a node higher than an eNodeB.

A program running on a device according to the present invention mayserve as a program that controls a Central Processing Unit (CPU) and thelike, and causes a computer to operate in such a manner as to realizethe functions of the above-described embodiment according to the presentinvention. Programs or the information handled by the programs aretemporarily read into a volatile memory, such as a Random Access Memory(RAM) while being processed, or stored in a non-volatile memory, such asa flash memory, or a Hard Disk Drive (HDD), and then read by the CPU tobe modified or rewritten, as necessary.

Moreover, the devices in the above-described embodiment may be partiallyenabled by a computer. In such a case, a program for realizing suchcontrol functions may be recorded on a computer-readable recordingmedium to cause a computer system to read the program recorded on therecording medium for execution. It is assumed that the “computer system”refers to a computer system built into the devices, and the computersystem includes an operating system and hardware components such as aperipheral device. Furthermore, the “computer-readable recording medium”may be any of a semiconductor recording medium, an optical recordingmedium, a magnetic recording medium, and the like.

Moreover, the “computer-readable recording medium” may include a mediumthat dynamically retains a program for a short period of time, such as acommunication line that is used to transmit the program over a networksuch as the Internet or over a communication line such as a telephoneline, and may also include a medium that retains a program for a fixedperiod of time, such as a volatile memory within the computer system forfunctioning as a server or a client in such a case. Furthermore, theabove-described program may be configured to realize some of thefunctions described above, and additionally may be configured to realizethe functions described above, in combination with a program alreadyrecorded in the computer system.

Furthermore, each functional block or various characteristics of thedevices used in the above-described embodiment may be mounted orperformed on an electric circuit, that is, typically an integratedcircuit or multiple integrated circuits. An electric circuit designed toperform the functions described in the present specification may includea general-purpose processor, a Digital Signal Processor (DSP), anApplication Specific Integrated Circuit (ASIC), a Field ProgrammableGate Array (FPGA), or other programmable logic devices, discrete gatesor transistor logic, discrete hardware components, or a combinationthereof. The general-purpose processor may be a microprocessor, or theprocessor may be a processor of known type, a controller, amicro-controller, or a state machine instead. The general-purposeprocessor or the above-mentioned circuits may be constituted of adigital circuit, or may be constituted of an analog circuit.Furthermore, in a case that with advances in semiconductor technology, acircuit integration technology appears that replaces the presentintegrated circuits, it is also possible to use an integrated circuitbased on the technology.

Note that the invention of the present patent application is not limitedto the above-described embodiments. In the embodiment, devices have beendescribed as an example, but the invention of the present application isnot limited to these devices, and is applicable to a terminal device ora communication device of a fixed-type or a stationary-type electronicapparatus installed indoors or outdoors, for example, an AV apparatus, akitchen apparatus, a cleaning or washing machine, an air-conditioningapparatus, office equipment, a vending machine, and other householdapparatus.

The embodiments of the present invention have been described in detailabove referring to the drawings, but the specific configuration is notlimited to the embodiments and includes, for example, an amendment to adesign that falls within the scope that does not depart from the gist ofthe present invention. Furthermore, various modifications are possiblewithin the scope of the present invention defined by claims, andembodiments that are made by suitably combining technical meansdisclosed according to the different embodiments are also included inthe technical scope of the present invention. Furthermore, aconfiguration in which a constituent element that achieves the sameeffect is substituted for the one that is described in the embodimentsis also included in the technical scope of the present invention.

DESCRIPTION OF REFERENCE NUMERALS

-   1 (1A, 1B, 1C) Terminal device-   3 Base station device-   10 Radio transmission and/or reception unit-   11 Antenna unit-   12 RF unit-   13 Baseband unit-   14 Higher layer processing unit-   15 Medium access control layer processing unit-   16 Radio resource control layer processing unit-   30 Radio transmission and/or reception unit-   31 Antenna unit-   32 RF unit-   33 Baseband unit-   34 Higher layer processing unit-   35 Medium access control layer processing unit-   36 Radio resource control layer processing unit

1-4. (canceled)
 5. A terminal device, comprising: antenna circuitryconfigured to receive an Enhanced Physical Downlink Control Channel(EPDCCH); and radio transmission and/or reception circuitry configuredto monitor, in an EPDCCH-PRB-set p in a subframe k, a first set ES_(k)^((L)) of first EPDCCH candidates and a second set ES_(k) ^((L)) ofsecond EPDCCH candidates, wherein the first set ES_(k) ^((L))corresponds to a first Carrier Indicator Field (CIF) value and a firstaggregation level L, the second set ES_(k) ^((L)) corresponds to asecond CIF value and the first aggregation level L, a first numberM_(p,c) ^((L)) of the first EPDCCH candidates is determined according toat least α_(p,c) indicated by first information and M_(p) ^((L)), asecond number M_(p,c) ^((L)) of the second EPDCCH candidates isdetermined according to at least α_(p,c) indicated by second informationand the M_(p) ^((L)), first Enhanced Control Channel Element(s)(ECCE(s)) corresponding to the m^(th) first EPDCCH candidate included inthe first set ES_(k) ^((L)) and second ECCE(s) corresponding to them^(th) second EPDCCH candidate included in the second set ES_(k) ^((L))are determined according to at least a first value, and the first valueis given by an expression: $\begin{matrix}{{{{floor}\left( \frac{m \cdot N_{{ECCE},p,k}}{L \cdot M_{p}^{(L)}} \right)}\mspace{14mu} {where}}{{m = 0},1,\ldots \mspace{14mu},{M_{p,c}^{(L)} - 1},}} & \left\lbrack {{Expression}\mspace{14mu} 19} \right\rbrack\end{matrix}$ where N_(ECCE,p,k) is a total number of ECCEs included inthe EPDCCH-PRB-set p in the subframe k, and floor is a functionreturning a value obtained by rounding down an input value after adecimal point.
 6. A base station device, comprising: radio transmissionand/or reception circuitry configured to code Downlink ControlInformation transmitted by using an Enhanced Physical Downlink ControlChannel (EPDCCH); and antenna circuitry configured to transmit theEPDCCH in each of a first set ES_(k) ^((L)) of first EPDCCH candidatesand a second set ES_(k) ^((L)) of second EPDCCH candidates in anEPDCCH-PRB-set p in a subframe k, wherein the first set ES_(k) ^((L))corresponds to a first Carrier Indicator Field (CIF) value and a firstaggregation level L, the second set ES_(k) ^((L)) corresponds to asecond CIF value and the first aggregation level L, a first numberM_(p,c) ^((L)) of the first EPDCCH candidates is determined according toat least α_(p,c) indicated by first information and M_(p) ^((L)), asecond number M_(p,c) ^((L)) of the second EPDCCH candidates isdetermined according to at least α_(p,c) indicated by second informationand the M_(p) ^((L)), first Enhanced Control Channel Element(s)(ECCE(s)) corresponding to the m^(th) first EPDCCH candidate included inthe first set ES_(k) ^((L)) and second ECCE(s) corresponding to them^(th) second EPDCCH candidate included in the second set ES_(k) ^((L))are determined according to at least a first value, and the first valueis given by an expression: $\begin{matrix}{{{{floor}\left( \frac{m \cdot N_{{ECCE},p,k}}{L \cdot M_{p}^{(L)}} \right)}\mspace{14mu} {where}}{{m = 0},1,\ldots \mspace{14mu},{M_{p,c}^{(L)} - 1},}} & \left\lbrack {{Expression}\mspace{14mu} 20} \right\rbrack\end{matrix}$ where N_(ECCE,p,k) is a total number of ECCEs included inthe EPDCCH-PRB-set p in the subframe k, and floor is a functionreturning a value obtained by rounding down an input value after adecimal point.
 7. A communication method used for a terminal device, thecommunication method comprising: receiving an Enhanced Physical DownlinkControl Channel (EPDCCH); and monitoring, in an EPDCCH-PRB set p in asubframe k, a first set ES_(k) ^((L)) of first EPDCCH candidates and asecond set ES_(k) ^((L)) of second EPDCCH candidates, wherein the firstset ES_(k) ^((L)) corresponds to a first Carrier Indicator Field (CIF)value and a first aggregation level L, the second set ES_(k) ^((L))corresponds to a second CIF value and the first aggregation level L, afirst number M_(p,c) ^((L)) of the first EPDCCH candidates is determinedaccording to at least α_(p,c) indicated by first information and M_(p)^((L)), a second number M_(p,c) ^((L)) of the second EPDCCH candidatesis determined according to at least α_(p,c) indicated by secondinformation and the M_(p) ^((L)), first Enhanced Control ChannelElement(s) (ECCE(s)) corresponding to the m^(th) first EPDCCH candidateincluded in the first set ES_(k) ^((L)) and second ECCE(s) correspondingto the m^(th) second EPDCCH candidate included in the second set ES_(k)^((L)) are determined according to at least a first value, and the firstvalue is given by an expression: $\begin{matrix}{{{{floor}\left( \frac{m \cdot N_{{ECCE},p,k}}{L \cdot M_{p}^{(L)}} \right)}\mspace{14mu} {where}}{{m = 0},1,\ldots \mspace{14mu},{M_{p,c}^{(L)} - 1},}} & \left\lbrack {{Expression}\mspace{14mu} 21} \right\rbrack\end{matrix}$ where N_(ECCE,p,k) is a total number of ECCEs included inthe EPDCCH-PRB-set p in the subframe k, and floor is a functionreturning a value obtained by rounding down an input value after adecimal point.
 8. A communication method used for a base station device,the communication method comprising: coding Downlink Control Informationtransmitted by using an Enhanced Physical Downlink Control Channel(EPDCCH); and transmitting the EPDCCH in each of a first set ES_(k)^((L)) of first EPDCCH candidates and a second set ES_(k) ^((L)) ofsecond EPDCCH candidates in an EPDCCH-PRB-set p in a subframe k, whereinthe first set ES_(k) ^((L)) corresponds to a first Carrier IndicatorField (CIF) value and a first aggregation level L, the second set ES_(k)^((L)) corresponds to a second CIF value and the first aggregation levelL, a first number M_(p,c) ^((L)) of the first EPDCCH candidates isdetermined according to at least α_(p,c) indicated by first informationand M_(p) ^((L)), a second number M_(p,c) ^((L)) of the second EPDCCHcandidates is determined according to at least α_(p,c) indicated bysecond information and the M_(p) ^((L)), first Enhanced Control ChannelElement(s) (ECCE(s)) corresponding to the m^(th) first EPDCCH candidateincluded in the first set ES_(k) ^((L)) and second ECCE(s) correspondingto the m^(th) second EPDCCH candidate included in the second set ES_(k)^((L)) are determined according to at least a first value, and the firstvalue is given by an expression: $\begin{matrix}{{{{floor}\left( \frac{m \cdot N_{{ECCE},p,k}}{L \cdot M_{p}^{(L)}} \right)}\mspace{14mu} {where}}{{m = 0},1,\ldots \mspace{14mu},{M_{p,c}^{(L)} - 1},}} & \left\lbrack {{Expression}\mspace{14mu} 22} \right\rbrack\end{matrix}$ where N_(ECCE,p,k) is a total number of ECCEs included inthe EPDCCH-PRB-set p in the subframe k, and floor is a functionreturning a value obtained by rounding down an input value after adecimal point.